Abstract
BAD (BCL-2 antagonist of cell death) is a pro-apoptotic BCL-2 family protein that plays a critical role in the regulation of apoptotic response. This study presents direct evidence that AF1q increased the radiation-induced apoptosis through up-regulation of BAD in human squamous carcinoma A431 cells and the key transcription factor involved is NF-kappaB. The minimal promoter sequence of BAD was identified; the activity was increased in AF1q stable transfectants and decreased upon AF1q siRNA transfection. The NF-kappaB consensus binding sequence is detected on BAD promoter. Inactivation of NF-kappaB by NF-kappaB inhibitor Bay 11-7082 or NF-kappaB p65 siRNA suppressed the expression and promoter activity of BAD; the suppression is more obvious in AF1q stable transfectants which also have an elevated NF-kappaB level. Mutation of putative NF-kappaB motif decreased the BAD promoter activity. The binding of NF-kappaB to the BAD promoter was confirmed by chromatin-immunoprecipitation. These findings indicate that AF1q up-regulation of BAD is through its effect on NF-kappaB and this may hint of its oncogenic mechanism in cancer.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Apoptosis / drug effects
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Apoptosis / genetics*
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Apoptosis / radiation effects*
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Base Sequence
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Blood Proteins / antagonists & inhibitors
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Blood Proteins / genetics
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Blood Proteins / physiology*
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Carcinoma, Squamous Cell / genetics
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Carcinoma, Squamous Cell / metabolism
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Carcinoma, Squamous Cell / pathology*
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Cell Line, Tumor
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Gamma Rays
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Gene Expression Regulation, Neoplastic / drug effects
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Gene Expression Regulation, Neoplastic / radiation effects
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Humans
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Molecular Sequence Data
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NF-kappa B / antagonists & inhibitors
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NF-kappa B / genetics
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NF-kappa B / metabolism
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NF-kappa B / physiology*
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Neoplasm Proteins / antagonists & inhibitors
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Neoplasm Proteins / genetics
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Neoplasm Proteins / physiology*
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Promoter Regions, Genetic
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Protein Binding
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Proto-Oncogene Proteins
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RNA, Small Interfering / pharmacology
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Transcription, Genetic / drug effects
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Transcription, Genetic / genetics
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Up-Regulation / drug effects
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Up-Regulation / genetics
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bcl-Associated Death Protein / genetics*
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bcl-Associated Death Protein / metabolism
Substances
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BAD protein, human
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Blood Proteins
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MLLT11 protein, human
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NF-kappa B
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Neoplasm Proteins
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Proto-Oncogene Proteins
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RNA, Small Interfering
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bcl-Associated Death Protein